Commit e7f7dcadf97accf7a3f0fca58c8d3b4ffb563808
Committed by
Greg Kroah-Hartman
1 parent
4eed408a0b
sparc64: Fix pcr_ops initialization and usage bugs.
[ Upstream commit 8bccf5b313180faefce38e0d1140f76e0f327d28 ] Christopher reports that perf_event_print_debug() can crash in uniprocessor builds. The crash is due to pcr_ops being NULL. This happens because pcr_arch_init() is only invoked by smp_cpus_done() which only executes in SMP builds. init_hw_perf_events() is closely intertwined with pcr_ops being setup properly, therefore: 1) Call pcr_arch_init() early on from init_hw_perf_events(), instead of from smp_cpus_done(). 2) Do not hook up a PMU type if pcr_ops is NULL after pcr_arch_init(). 3) Move init_hw_perf_events to a later initcall so that it we will be sure to invoke pcr_arch_init() after all cpus are brought up. Finally, guard the one naked sequence of pcr_ops dereferences in __global_pmu_self() with an appropriate NULL check. Reported-by: Christopher Alexander Tobias Schulze <cat.schulze@alice-dsl.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Showing 3 changed files with 8 additions and 3 deletions Side-by-side Diff
arch/sparc/kernel/perf_event.c
... | ... | @@ -1671,9 +1671,12 @@ |
1671 | 1671 | |
1672 | 1672 | static int __init init_hw_perf_events(void) |
1673 | 1673 | { |
1674 | + int err; | |
1675 | + | |
1674 | 1676 | pr_info("Performance events: "); |
1675 | 1677 | |
1676 | - if (!supported_pmu()) { | |
1678 | + err = pcr_arch_init(); | |
1679 | + if (err || !supported_pmu()) { | |
1677 | 1680 | pr_cont("No support for PMU type '%s'\n", sparc_pmu_type); |
1678 | 1681 | return 0; |
1679 | 1682 | } |
... | ... | @@ -1685,7 +1688,7 @@ |
1685 | 1688 | |
1686 | 1689 | return 0; |
1687 | 1690 | } |
1688 | -early_initcall(init_hw_perf_events); | |
1691 | +pure_initcall(init_hw_perf_events); | |
1689 | 1692 | |
1690 | 1693 | void perf_callchain_kernel(struct perf_callchain_entry *entry, |
1691 | 1694 | struct pt_regs *regs) |
arch/sparc/kernel/process_64.c